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package httprp
import (
"context"
"net/http"
"net/http/httputil"
"net/url"
)
// RequestFunc may take information from an HTTP request and put it into a
// request context. BeforeFuncs are executed prior to invoking the
// endpoint.
type RequestFunc func(context.Context, *http.Request) context.Context
// Server is a proxying request handler.
type Server struct {
proxy http.Handler
before []RequestFunc
errorEncoder func(w http.ResponseWriter, err error)
}
// NewServer constructs a new server that implements http.Server and will proxy
// requests to the given base URL using its scheme, host, and base path.
// If the target's path is "/base" and the incoming request was for "/dir",
// the target request will be for /base/dir.
func NewServer(
baseURL *url.URL,
options ...ServerOption,
) *Server {
s := &Server{
proxy: httputil.NewSingleHostReverseProxy(baseURL),
}
for _, option := range options {
option(s)
}
return s
}
// ServerOption sets an optional parameter for servers.
type ServerOption func(*Server)
// ServerBefore functions are executed on the HTTP request object before the
// request is decoded.
func ServerBefore(before ...RequestFunc) ServerOption {
return func(s *Server) { s.before = append(s.before, before...) }
}
// ServeHTTP implements http.Handler.
func (s Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
ctx := r.Context()
for _, f := range s.before {
ctx = f(ctx, r)
}
s.proxy.ServeHTTP(w, r)
}
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